I doubled the fluorescent light fixtures for my basement growing area. Now some of my paphs are turning very light green. Some are almost yellow. Have I overdone it? How can I tell if I have provided too much light for my paphs?

First, welcome to the forum, Terrence!

Second, well, photos always help, don't know if you can take a pic to show us just how light in color your plants are. I find in general, my paphs can take a lot of light, but I tend to grow just the strap-leafed multi floral types for the most part. No mottled leaved paphs at all, and they tend to like a little less. I don't grow under flourescents either so I am hoping someone who does will weigh in. One thing you could do is lessen the amount of hours the lights are on, another might be to raise the lights a bit higher above the plants. A dose of epsom salts or another fertilizer with Cal/Mag might also help to green up your plants a bit.

A few of my plants are quite light (actually, most of the ones from Sherwood) shades of very light green/yellow from growing in very bright conditions. They always arrive very healthy and happy, so generally, I don't worry about it, as long as the roots are good and the plants are growing and blooming. I did noticed that a swtich to MSU fertilizer has greened up my roth from them, but it is still a light grassy green, just a little less yellow.

Don't know how much I helped, but good luck!

Welcome to the forum, Terrence!

What kind of Paphs are you growing? The multifloral strap leafed ones need very high light to bloom. With fluorescents, are you also providing natural direct sunlight? Like Heather suggested, photos and your grow conditions should help.

Welcome, Terrence! Were the Paphs nicely colored and growing well before you added the extra light? If so, it might be that you now need to increase your fertilizer concentration a little to help the plants as they attempt to utilize the extra light. This happened to me a couple of yearrs ago when I switched fertilizers and was very cautious about keeping the concentration low. Many of my plants started yellowing. I gradually increased my fertilizer concentration and my plants started greening up, again. Be cautious: SLOWLY INCREASE the concetration maybe 10% at a time until you see the plants begin to get greener.

Another good thing to do would be to unpot a couple plants and check the roots to make sure that they are still healthy. It might be that the uptake of nutrients is being impeded by the lack of healthy roots. Repotting would help that problem immediately.

Finally, another possibility is what Heather said. You may be missing or short on a particular nutrient that the plants need.

Good luck, keep us informed of what you try and whether it works or not. :D

I'd get a light meter. It's hard to get too much light from flourescent lights, and as Peter said some species (namely the big strap leaved multiflorals) like almost full sun.

We've had some discusions about yellowing, and it may be more due to bioavalability of nutrients based on the pH of your potting mix and fertilizer mix.

I do have a fc meter but my concern is my mottled leaf paphs, not my strappies. The meter says the plants are getting about 3,500 fc at the leaf level but I don't know how accurate the meter is. This is up about 500 fc from when I had one fixture over the paphs. Now I have two. I went with two fixtures because this setup distributes the light more evenly across the plants. In my old setup I know the plants along the edge of the light were not getting as much light as they needed. 3,500 fc sounds high to me based on what I have read. All of the plants are definitely lighter green now under the new setup. The new growth is coming out light green. However, some of the old growths are beginning to turn yellow, specially the oldest leaves. I also have heard that a little Epsom salt applied monthly might help green up yellow leaves and I have been adding 1/4 tsp per gallon monthly to my regular ArgoGro fertilizer that I use. I have been growing paphs about two years now so I am still learning as I go.

I cannot move the lights any higher because there is another shelf above and I cannot adjust the shelves. I can reduce the hours of light but to do that I would have to get a second timer. Right now my lights are on 16 hours a day. My mini-catts love this and rebloom regularly for me. If I had a second timer I could adjust my paphs to fewer hours but they would still get some spill-over light from the nearby mini-catt shelf.

I am adding a link so that you can see what I have rebloomed under lights. Check this out: http://www.ttviews.com/Garden/Indoor%20Garden/orchids121.htm . I have had problems reblooming phrags that I had purchased in bud. To work on that problem I purchased a 4-tube 48" T-5 fluorescent light setup. T-5 are high output tubes and boy are they bright. My fc meters goes off its 5000 fc top number when I put the probe right again the light. I am getting 5000 to 4000 fc at the leaf level of my phrags and taller strap leaf paphs. Since I put up the light (about two moths ago) two of my phrags that haven't bloomed since I got them 18 months ago have put out buds. That pleases me a lot.

I really doubt that you can burn plants under fluorescents even the mottled ones because I grow all my mottled ones with my multis directly under my HPS light system and they never get burned. What kind of Phrags are you having problem reblooming? I ask because some Phrags require very bright light to rebloom properly.

The ones that have budded recently are Phrag. Don Wimber (Red) (Phrag. Eric Young x Phrag. Besseae) and Phrag. Cape Sunset ( Eric Young x schlimii). The ones that have not rebloomed for me are Phrag. Dick Clements 4N x pearcii 'Birchwood' AM/AOS, Phrag. Sedenii 'Blush' (Phrag. schlimii x Phrag. longifolium) and Phrag. Iron Works (longifolium X Sorcerer's Apprentice). I expect that the very bright high-output T-5 fluorescent lights might do the trick.

I think I will continue to keep the four light setup over my mottled leaf paphs for a while and see what happens. I know light green means faster growing. Maybe I will get reblooms quicker with the brighter lings.

If it is mineral defficiency(probably magnesium) try mixing Epsom Salts @ 1 teaspoon per gallon
& try this on 1 plant, the plant should "green up" as you watch it.
With the very low fert & bright lights(3,500fc + ) my largest roth was very yellow last year.
After the Epsom salts it went to mid green in minutes , it is very cool to watch the change.
I supplement calcium/magnesium more regularly now.

Terrence

Wow!!!!!! I visited your Gallery. It is awesome. I was really struck by the birds.

I also installed 4 - 48" T5 lights over two of my trays. I have them over only two trays but I may at a later date, if I need more trays, install another one. I have some vi-tec 93 lights also and can't believe how much brighter the T5 lights are. Another thing I like about them they, don't glare like the HID lights. I have them in my computer room and love the lighting effect.

Grandma

Grandma: Thanks for looking. I love taking bird photos. Do you like garden photos? My web also has some photos I took of some gardens in Europe. You can find the garden photos at www.ttviews.com. I am strictly an amateur photographer although I did get a few photos published in my journalist days.

Dwayne: Thanks for the epsom salt update. I have tried 1/4 tsp per gallon but maybe that was not enough. So I just did tried the 1 tsp per gallon mixture on a two-growth Paph. Marcella Noble (Paph. sukhakulii x Paph.stonei) plant that is very light green. It has two nice growths but hasn't bloomed during 18 months I have had it.

Terrence

Terrence

I went through all of them. It took two cups of coffee. I loved them all and will possibly go into your post again tomorrow morning with my coffee.

They all were wonderful but I was taken in by the beautiful shots you got of those birds. They almost said 'Here I am, take my picture'.

Grandma

Terrence
3500fc is allot for mottled leafs in the barbata section, and would probably like it to be closer to 1500fc.

3500 is allot of FC for flourescents. Are you sure you are not reading lumens? I use a calibrated light meter in my lab, and could barely get 700fc from a multi light setup 3 to 5 inches from the plants.

I suspect that my fc meter isn't that accurate. I believe its running about a 1000 fc too high. How do you calibrate a meter?

I have the vitek-93s as well, just measured my light, using my camera - am getting around 750fc at 9 inches from the lights. Which isn't bad. I have the seedlings at that distance, move the lights closer for adult plants.

The try camera-light-meter method and see what you get:
http://www.geocities.com/orchidsnzpaph/LIIGHT_MEASUREMENT.htm

I suspect that my fc meter isn't that accurate. I believe its running about a 1000 fc too high. How do you calibrate a meter?


We can zero it in house, but we have to send it to the manufacturer to calibrate.

I also have a little meter that has multiple ranges to select for. Sometimes it also uses a 10:1 sheild over the photocell for bright samples.

If it is mineral defficiency(probably magnesium) try mixing Epsom Salts @ 1 teaspoon per gallon
& try this on 1 plant, the plant should "green up" as you watch it.
With the very low fert & bright lights(3,500fc + ) my largest roth was very yellow last year.
After the Epsom salts it went to mid green in minutes , it is very cool to watch the change.
I supplement calcium/magnesium more regularly now.

Dwight: I followed your epson salt suggestion about four days ago and the result has been immediate and amazing. I had three paphs that were downright yellow. They already are greening up. That was a great suggestion! Thanks.

Magnesium is the core atom in chlorophyl (kinda like iron the core atom in hemoglobin). So with more Mg you can get more greenstuff. Its kinda like a version of anemia.

I use MgOH or "Magox" for the same purpose, but it can raise the pH so you need to monitor pH in the fert mix when you use it.

Okay, I am going to try this on a few of mine tomorrow.
Rick, can I add it instead of protekt to raise my pH back up? And I am assuming I use it 1 tsp/gallon in addition to my regular fertilizer mix?

Thanks for the clarification!
Heather

Are you talking about Magox or epson salts? Epson salts won't change pH much at all and I think Ed M has used it at a much higher rate than 1tsp/gal.

Magox on the other hand will increase the pH, and you have to be careful because it does so very slowly compared to KOH.

I use Magox in small quanties (<1/8 tsp/gal) after boosting the pH to 7.2 with the Protect. At this rate it ends up between 7.5 and 8.0. (and this is only for my calcareous species and roths). A 1/2tsp per gal of Magox could send the pH to >10. :shock:

Epsom salts (I already have that in the arsenal.)
Thanks Rick!